Recombinant Core Streptavidin 3 (r-cSA3 )
- SKU:
- GEN-NRPA35S
- Formulation:
- Lyophilized from 5 mM PB (4 mM Na2HPO4, 1 mM NaH2PO4, pH 7.4)
- Mol. Weight.:
- 13.5 kDa
- pI theoretical:
- 8.27
- Purity:
- ≥95% (SDS-PAGE analysis)
- A280nm (1 mg / mL):
- 3.52
- Endotoxin:
- ≤5EU / mg
- Resources:
- Escherichia coli (E. coli)
- Storage condition:
- -20 ℃
- Storage period:
- 3 years
Description
Streptavidin (SA) has a strong affinity with biotin. The affinity constant Kd can generally be as high as 10-15 M. Active SA usually exists as a tetramer. Because SA does not contain sugar groups, SA has a lower level of non-specific binding than avidin in detection applications. It has been widely used in enzyme-linked immunosorbent assay, immunohistochemistry, time-resolved immunofluorescence technology (TRFIA), quantitative PCR, single-stranded DNA preparation, biomolecule-purification, preparation of monoclonal antibodies and other biotechnology fields.
However, the very high affinity of SA and biotin generally makes it difficult to separate the combined SA from biotin by a gentle method. Conditions that can be separated generally render SA inactive, as well as biotin-labeled antibodies and antigens. Therefore, it is generally considered that the combination of SA and biotin is irreversible. Recombinant central streptavidin 3 (r-cSA3) is modified from native streptavidin at the molecular level by removing the binding force to form tetramers. r-cSA3 is an active monomer, but its affinity for biotin is strongly weakened (Kd≈10-7M), achieving reversible binding and dissociation. It can be used for gentle separation and purification of proteins, antibodies, nucleic acids and other biotinylated materials.